Semiautomatic telephone system



' E. D. VVILLISSv SEMIAU'JIOMATICv TELEPHONE SYSTEM Filedmay 31. 1919 f2 sheets-sheet 1 Imm; mlm Egfr-15rd D. Z/U'JfffE B. D. WILLES SMIAUTOMATIC TELEPHONE SYSTEM May 22, 1923.

Filled May 31 1919 2 Sheets-Sheet 2 Patented May 22, 19,23.

STATES.

1,455,95i ATENT oSFFlcE.--

jBERNARDJD. WILLIS, OF CHICAGO, ILLINOIS, ASSIGNOR T0 AUTOMATIC ELECTRIC l lCOMPANY, OF CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

SEMIATOMATVIC TELEPHONE sYs'rnuit.

Application led May 31,

T o all whom/t may concern.' v

'Be it known that I, BERNARD D. WILLIS, a citizen of the United States of America, and la resident of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Semiautomatic rllelephone Systems, of which the following is a specification.

My invention relates in general lto improvements in semi-automatic' telephone systems and. more specifically tol a two-way trunk circuit between a manual exchange and an automatic branch exchange.

Among the objects of my invention are the provision of means for extending connections either manually or kautomatically in one direction over a trunk line of the character described, together with the provision of means whereby certain calls may be extended over the trunk automatically to the main exchange without calling in the attendant oroperator at the branch exchange,

and whereby other calls, which may require.

a charge or other control by the operator, will always be held up to bring the attendant in on the connection before'it can be exsion,v of the connection until` theope'rator val-I tended to the main exchange. In thismanner the attendant at the branch exchange will be informed as to-all callswhich go to the main exchange in which she is interested. In order vto accomplish this result I have provided multipled terminals for theytrunk in the banks of a selector switch in more than one level thereof together with dis,- criminating means whereby ,if vthe trunk is called thrugh one level of this switch, then the-call may proceed withoutfthe operators attention, while vif thel .trunk is called through another level'or .multiple the selector switch, means isoperatedtols1gnal the operator and toprevent 1 further extenlows such extension.

shofw by means' of theusufal' circu'itfdiagrams the equipment neces/sary `Vfor an understanjd The .preferred embodiment of ymy invention .is illustrated in the', acconfipiyinyin'gdraw,d` ings, .compring FigS'5`1,.2 and 3, which in Vof'the's'everalfeaturesofnovelty. i f

callsreceivedf from the main c f01z1s10nt1f01-lina any., ut. the branch exchange. In Eig.

bange? andi iashown at SiritQhSiIlcauses the signal 165110'v 1919. serial No. 301,038.

by a calling ysubscriber in the branch exchange through the medium of aline lswitch or a selector. y

(In Fig. 2 I have shown a trunk line lbetween two exchangestermina'ting iny a jack J before the attendant operator at the branch exchange, in a jack J in the main exchange and in the multipled banks of the selector D (Fig.

I will first explain the' method by which the attendant at the branch exchange calls the operator at the main exchange. 'When the attendant receives an order for a call to the main exchange the plug P of the cord circuit O is inserted into. the jack J (Fig. 2). The insertion of plug P closes a circuit from ground through the sleeve of plug 1P, sleeve of jack J, springs 2 and 3 and visual signal 4 to battery. A branch of this circ-uit extends lto the sleeve of the jack J2, another branch through the springs 17 and 18 to the test cqntacts of the 'trunk in the banks of the selector'D 3),- and another branch extends through re ay 23.110 battery. Relay 23 energizes to disconnect the relay 24 and relay 22 from the trunk circuit and closes springs 25. A further result of the insertion lof the plug is the closure of a circuit from ground through s rings 5, springs 6 and 21, ring of jack J, p ug springs 7, winding 8, relay 9, winding 10, springs 11, tip of plug P and jack J, springs 12 and A13, springs 14, and relay 15 td battery. The current in this circuit is of the proper direction to cause relay 9 to attract itsy `armature to light the lamp 16 in thegcord circuit, and relay 15 energizes to light the lamp 19 before'y the main exchange operator. The operator at the mai'nexchange, upon'seeng the lampv 19' lighted, inserts' the plug of her cordcircuit to two wire side switchless type-whi'ch/is well known' 1n the art and which maybe seized J and"v ground tothe "tipsidefoffthe jakJ This it willl befsg'en"mise's a lreversaltrl "bt- 1 retired.v 'Thes arti. y. t

extended to the desired subscriber in thev regular manner and when completed, and

\ the main exchange operator removes the plug from the jack J', then relay 9 in the cord O will operate to give a disconnect signal to the attendant operator.

In case o a call in the opposite direction from the main to the branch exchange, the main exchange operator after testing the jack J inserts her plug into said jack and by a ringing key (not shown) projects generator current out over the conductors of the trunk line to operate the bridged relay 24. Relay 24 closes the circuit of the Icall signal lamp 26 before the attendant who then inserts the answering plug P Ainto the jack J to answer the call. In this case it will be seen that the relay 27 is in bridge of the trunk circuit as was the relay 9 in the preceding call and operates in a similar manner to give the proper supervision. It will be seen also that the attendant operators cord O is provided with a calling device 28 and a two way key K which may be operated to connect said calling device to either the answering or to the calling end of her cord circuit, the calling end in this case, and she may therefore operate the automatic switches of the branch exchange to extend the connection to a de-A sired automatic subscriber.

I will now describe the manner in which one of the subscribers in the automatic branch exchange may seize the trunk line to the main exchange and signal the operator thereat without calling through the attendant operators cord circuit. It will be assumed for the purposes of this description that there are certain subscribers in the branch vexchange who are entitled to free service to the main exchange and certain others who must not be allowed to call the main exchange unless they are first charged for such a connection. In order to accomplish this result, the free subscribers are instructed to call one number when calling the mainexchange and the pay subscribers are instructed to call another number. That is, the trunk line is multipled into two levels (or more) of the selectors of the branch exchange (similar to D) 'and when the trunk is called over one level the call may proceed without calling in the attendant and when called through another level by the pay servicenumber then the call is blocked and the attendant'called in. I will first rdescribe the operation of the apparatus and circuits when a free service subscriber calls the main exchange.

It will be understood that the selector D is one 'of a number of similar selectors having access to trunk lines to connectol` cal magnet 32 and rotary magnet. 33 to raise its wipers to a desired level and to tutolmatically select an idle trunk in-that eve Assuming that for,y free calls the trunks are located in the 9th level of the selector, one of which sets of contacts are shown at 35, 36 and 37, when the selector has seized this set of contacts 35, 36 and 37, and relay 34 has energized to switch the calling line to the trunk, then a circuit is completed through the line relay 38 of the trunk in series with the calling line circuit. Relay 38 energizes to close the springs 39 `in the circuit of relay 40 and springs 41 to close the trunk circuit. At the same time ground is applied to the contact 37 from the selector to make the trunk busy to further automatic calls. Contact 37 is connected through springs 17 and 18 to the sleeve of jack J2 and to visual signal 4, which operates to indicate the busy condition of the trunk to the operator. Another branch extends through springs 3 and 2, and through relay 23 to battery, energizing relay -23 to disconnect relays 22 and 24 from the trunk. Relay 40 energizes to supply ground direct to this same holding and busying circuit at springs 42 and 43, and closes a circuit for relay 45 at springs 44. Relay 45 energizes to open the springs 46 and to close s rings 47 to busy the trunk at its multip e test contact 48 in the 10th level and also to energize the slow relay 49. Relay 49, upon energizing completes the connection with the trunk to the main exchange at springs 5() and 51 and'cornpletes a circuit as follows: From ground through springs 5 at the main exchange end of 'the trunk, springs 50, winding 52, springs 41, winding 54, springs 51, springs 14, and relay 15 to battery. Relay 15 energizes in the manner previously pointed out to operate the signal 19 before the main exchange operator. The operator will answerths signal by plugging into the jack J and extend the connection to a desired subscriber in the main exchange. The relay 15 is cut off by the operator in the lnanner explained.` Now should lthe calling subscriber hang up before the operator removes the plug at the main exchange, then relay 38 will fall back and open the s rings 41\to remove the short circuit from t e pois removed. As soon as the callin 'hangs up and relay 53 is inserted 1n the larized relay 53. Relay 53 is adapted to and its back contact, to the various jack sleeves and. test contacts of the trunk to maintain 'the trunk line busy until the plug man circuit to the main exchange, the relay 56 at the main exchange cord circuit falls back to give the operator a disconnect sig- (lll nal.

I will now describe the operations when a restricted service line, or one which must be charged for calls to the main exchan e, calls the trunk via the 10th level of t e selector D. ln this case the call will progress inthe same manner except that the selector Dwill connect with contacts'such as 57, 58-and 48 in the 10th level of the selector. In this case the relay 38 will energize in the same manner as previously de-4 scribed.` The private wiper of the switch vD, however, when connecting with ,the contact 48 brings about the following result. lVhen relay 40 energizes ground is fed through springs 42 and 43 and in this case through a special relay 60 to contact 48 and thence through relay 34 of the selector and relay 70 to battery. Relay 60 energizes to open the springs 6l in the circuit of slow relay 49 to prevent connection with the trunk line, opens the springs 62 and 63 to prevent relay 45 from short circuiting the relay 60, and closes springs 63 and 64 so that when Arelay 45 energizes, ground is connected through springs 47, 63 and 64 through the lamp signal 65 to battery. The springs 42 and 43 may be adjusted to make contact before the springs 44 so 'that relay 60 will energize before relay 45. Whenfthe attendant o erator at the branch exchange sees the signal 65 she inserts the plug of her cord into the special jack J2 and is ythereby connected through the repeating coil windings 52, 54, etc., so that she can first converse with the calling subscriber to ascertain his number and the wanted number in order to make out acharge ticket for the call. As soon as the operator 'obtains the desired information she resses a nonlocking key K with the fol owing result: Ground is supplied direct to the contact 48 thereby short circuiting the relay 60 and allowing said relay to fall back. It will be understood that a busy potential is supplied to contact 48 through the relay 60 to 1orevent any connection therewith until said contact is directly grounded. As soon as relay 60 falls back and closes the springs 62 and 63 it shorts itself out by ground through springs 47 and will therefore not energize again when key K is released. Relay 60 also lcloses springs 61 which now complete the circuit of relay 49 and allows said relay to energize to connect the calling liney through to the trunk and to the main exchange. After this the call may progress in the same manner as when a free service subscriber is calling and as has been described.

It will be seen therefore that Ihave pro-v vided a very ecient type of two way trunk line which gives two way service manually and one Way service automatically Wit proper su ervision, and having the further feature o allowing certain automatic subscribers unrestricted service over the trunk line while other automatic subscribers cannot call the main exchange without notice being given to the branch exchange opera-v tor. It will be understood, of course, that the service restriction imposed on the second class of subscribers depends on the fact that such subscribers do not know the main exchange can be reached free by callin a different number. This plan is simple an inexpensive and usually works well in practice, but if it is desired to positively prevent the restricted service su scribers from calling the free service number the selectors, such as the selector D, may be replaced by selectors of the type shown andl described in the United States patent to Powell, No. 1,350,882, granted August 24, 1920. A selector of the type shown 1n the patent named, when used in conjunction with the proper line switches, will give service on a certain level to some subscribers but not to the others.

Having fully described and ascertained the various features and as ects of my invention, what l consider to e new and desire to have protected by Letters `Patent will be pointed out in the appended claims.

What I claim as my invention is: y

l. In a telephone system, a first operator, a second operator, a trunk line extending between the two, a signal associated with each operator, a pair of terminals associated with one end of said trunk, ymeans for seizing either of said terminals to extend a connecttion to said trunk, and whereby whenl one of said terminals is seized the first signal only is automatically operated and whereby when the other one of the 'terminals is seized the second signal only is automatically operated.

2. In a telephone system, a rst manual board and a .setond manual board, an oper-l terminals associated with` one end of said trunk, means for seizing the first set of ter- .minals and for thereby automatically operating the signal at the first board only and 'for talking with the operator at the first board through said terminals, said means also for seizlng the second set of terminals and for thereby automatically operating the signal at the second board only, and for talking with the operator at the second board through the second terminal.

3. lin a telephone system, a rst manual board and a second manual board, an operator at each board, a trunk line connecting the two, a signal associated with each board, a rst set of terminals and a second set of ,terminals associated with one end of said trunk, means for seizing the first set of terminals and for thereby automatically operating the signal at the first board only and for talking with the operator lat the first board through said terminals, said means also for seizing the second set of terminals and for thereby automatically operating the signal at the second board only, and for talking with the operator at the second board through the second terminal, said means also for connecting said sets of terminals with said trunk for causing the operation of the signal at the first board whereby conversation may be had with the second operator throu Vh the second set of terminals.

4. n a telephone system, a first manual board and a second manual board, an operator at each board, a trunk line connecting the two, a signal associated with each board1 a first set of terminals and a second set of terminals individual to one end ofsaid trunk, means for seizing the first set of terminals and for thereby automatically operating the signal at the first board only and for talking with the operator at the first board through said first set of terminals, said means also for seizing the second set of terminals and for thereby automatically operating the signal at the second board only, and for talking with the operator at the second board throu h the second set of terminals.

A5|. n a telephone system, a first manual board and 'a second-manual board, anoperator at each board, a trunk line connecting the two, a'signal associated with each board, a first set of terminals and a second set of terminals individual to one end of said trunk, means for seizing the first set of terminals and for thereby automatically operating the signal at the first board only and for vtalking with the operator at the first board through said set of terminals, said means also for seizing the second set of terminals and for thereby operating the signal at the second board only, and for talking with the operator at the second board through the second terminal, said means also for connecting said sets of terminals with said trunk for causing` the operation ofthe signal at the first board whereby conversation may be had with the second operator through the second set of terminals.

6. lin a telephone system, a trunk line, a signal associated with each end 0f said trunk line, a pair of terminals for said trunk line, means for seizing one terminal for operating one of' said signals over said trunk line,means for seizing the other terminal andy for operating the other signal over a circuit excluding the trunk line, and means for thereafter connecting said second terminal with said trunk line for operating said first signalover said trunk line and over said second terminal.

7. ln a telephone system, a trunk line, an operators position, an automatic switch, a pair of branches for y said trunk line accessible to said automatic switch, another branch of said trunk leading to said operators position, means for preventing the completion of a connection over said trunk line and for signaling said operator when theautomatic switch seizes one branch of said trunk line. and means for extending a connection over said trunk line without signaling the operator when the automatic switch seizes the the other branch.

8. ln a telephone system, a trunk line, an automatic switch, a pair of branches for said trunk line accessible to said automatic switch, another branch of said trunk leading to an operator, means for preventing the completion of a connection over'said trunk line and for signaling said operator when the automatic switch seizes one branch of said trunk line, means for extending a connection over said trunk line without signaling the operator when the automatic switch seizes the other branch, and means controlled by the operator for permitting the comple- Ation of a connection over the trunk line after she has been signaled.

9. In a telephone system, a trunk line, a signal at each end thereof, a pair of branches at one end of said trunk line, means for seizing either of said branches, means responsive to the seizure of one of said branches for operating the signal at the opposite end of the trunk, and means responsive to the seizure of the other of said branches for preventing the operation of said second means and for operating the signal at the rear end of said trunk.

'10. ln a telephone system, an operator, a trunk line, a signal at each end thereof, a pair of branches at one end of said trunk line, means for seizing either of said branches, means responsive to the seizure of one of said branches for operating the signal at the opposite end of the trunk, means rel sponsive to the seizure of the other of said branches for preventing the operation of said second means and for operating the 'branches for operating` the /signal at the far end of said trunk, and a relay in the other branch responsive to the seizure of said other branch for preventing the operation of said first relay and for operating the signal at 'the near end of the trunk.

12. In va telephone system, a trunk line, a signal at each end thereof, a pair of branches for said trunk, means for seizing either branch to extend a connection, a relay responsive to the seizure of. one of said branches for operating the signal at the far end of said trunk, a relay in the other branch responsive to the seizure of said other branch for preventing the operation of said first relay and foroperating the signal at the nea-r end of the trunk, and means for rendering said first relay operative to operate the signal at the far end after the signal at the near end is operated.

13. in a telephone system, a trunk line having two incoming branches for receivin calls, selector switches for extending ca ls to said trunk by way of either branch, two outgoing branches over which calls may be automatically yrouted away from the trunk independent of subscriber control, one of said last mentioned branches being normally connected and the other being no rmally disconnected, a relay for connecting the normally disconnected branch to the trunk, a circuit for said relay excluding the talking conductors of the trunk, means for closing said -circuit when a call is received, said means including a relay energized over the two talking conductors of said trunk in series, and another relay for preventing the closure-of said circuit in case the call is received over a particular one of said incoming branches.

14. ln a telephone system, a trunk line having two incoming branches for receiv- 1n cal s to said trunk by way of either branch, two outgoing ,branches over which calls may be automatically routed away from the trunk independent of subscriber control, one osaid lastmentioned branches being normally disconnected, a relay for connecting the normally disconnected branch to the trunk, third conductors for said incoming branches, a relay energized over the trunk for completing a holding circuit for an voperated selector over the third conductor of the branch in use, anotherl relay connected in series with one of said third conductors calls, selector switches for extendingv but not with the other so that it will'energize only if a call is received via a particular branch, and a circuit for said connecting relay controlled by said series relay.

15. In a telephone system, a trunk line having two incoming branches for receiving calls, selector switches for extending calls to said trunk by way of' either branch, two outgoing branches over which calls may be automatically routed away from the trunk independent of subscriber control, one of said last mentioned branches being normally disconnected, a relay for connecting the normally disconnected branch to the trunk, third conductors for said incoming branches, a relay energized over the trunk for completing a holding circuitfor an operated selector over the third conductor of the branch in use, another relay connected in series with one of said third conductors but not with the other so that it will energize only if a call is received via a particular branch, and a circuit for said connecting relay closed under control of said trunk relay and opened by said series relay in case the latter is energized.

16. ln a telephone system, a trunk line extending from anlautomatic exchange to a manual exchange, automatic switches o erable in accordance with two different cal numbers for connecting calling automatic subscribers with said trunk, a checking operators switchboard at the automatic exchange, and relays operating automatically whenever the trunk is called by means of a particular one of the call numbers for temporarily preventing the completion of the call to the manual exchange and for signalling the checking operator.

' 17. ln a telephone system, a trunk line extending from an automatic exchange to a manual exchange, a line relay bridged across the line at the manual exchange in series with4 the exchange battery, a polar relay at the automatic end of the trunk non-responsive to normal current iow thereover, automatic switches in the automatic exchan e for extending connections to l the trun means in said trunk responsive to the seizure thereof by one of said switches for operating said line relay, means for cutting od the line relay when the operator answers the call and for reversing the direction of current flow over the trunk, said polar relay being responsive to such reversal of current, 5

and circuits controlled by said polar relay after the operated vautomatic switch is released for rendering the trunk line unselectable until it is cleared by the operator manual exchange, said trunk line comprising two normally d1sconnected sect1ons, au-

tomatic switches in the automatic for extending connections to the trunkya relay in the trunk responsive to the seizure thereof by one of said switches for connecting said sections, means at the manual exchange forsignaling the operator when the sections are connected, means whereby the operator can connect with the trunk to answer the call and establish a How of current over the trunk, a relay in bridge of the 'i first section energized by such current How,

a locking circuit for said first relay controlled by said second relay, and a guarding circuit also controlled by said secondv relay and effective to make the trunk line bus to said switches in case the operated switc is released before the trunk is disconnected by the operator.

Signed by me at Chicago, Cook County, illinois, this 29th day of May, 1919.

BERNARD D. WLLIS. 

